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    • Building Real-World Blockchain Fintech Products
    • Have hands-on experience on a broad range of real-world blockchain and fintech development patterns, including:
    • In-Place Upgrade from Windows Server 2003 to Windows Server 2025 with Active Directory Schema Update
    • In-Place Upgrade from Windows Server 2000 to Windows Server 2003 with Active Directory Schema Update
    • MD102 – Endpoint Administrator Labs
    • Tutorial: Design a relational database in Azure SQL Database C# and ADO.NET
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    • Interesting VMware Homelab Kits for 2025
    • Create as relational CMDB in MS SQL for inventory
    • What is Active Directory (Top 50 AD Questions Answered)
    • Memorabilia – Windows 2000

Building Real-World Blockchain Fintech Products

05.19.2025 by pablovillaronga //

Blockchain and Fintech-Use cases and Applications - M2P Fintech Blog

## πŸš€ **GitHub Repo Scaffolding**
“`
FirstChainPay/
β”œβ”€β”€ contracts/ # Smart contracts (Solidity)
β”‚ β”œβ”€β”€ PaymentGateway.sol # Main payment logic
β”‚ └── MockEURC.sol # Mock stablecoin for testing
β”œβ”€β”€ frontend/ # Next.js + Tailwind
β”‚ β”œβ”€β”€ pages/
β”‚ β”‚ β”œβ”€β”€ index.js # Landing page
β”‚ β”‚ └── dashboard.js # User payment dashboard
β”‚ └── styles/
β”œβ”€β”€ hardhat.config.js # Hardhat setup
β”œβ”€β”€ package.json
└── README.md # Project overview + setup
“`

—

## πŸ“… **Project Milestones (Visio-style Plan)**

![Project Plan](https://i.imgur.com/JQh7WDr.png)
*(Visual roadmap: Phases β†’ Tasks β†’ Deadlines)*

**Key Phases:**
1. **Smart Contract Development** (Weeks 1-3)
– Escrow logic
– Token conversion mock
2. **Frontend MVP** (Weeks 4-5)
– Wallet connection
– Payment form
3. **E-Commerce Integration** (Weeks 6-7)
– API endpoints
– Webhook simulator



πŸ’» **Starter Code**

### 2. **Frontend (`index.html` + JavaScript)**
“`html
<!DOCTYPE html>
<html>
<head>
<title>FirstChainPay</title>
<script src=”https://cdn.ethers.io/lib/ethers-5.2.umd.min.js”></script>
<style>
body { font-family: Arial; max-width: 600px; margin: 0 auto; }
button { padding: 10px; background: #4CAF50; color: white; border: none; }
</style>
</head>
<body>
<h1>FirstChainPay</h1>
<button id=”connectWallet”>Connect MetaMask</button>
<div id=”walletAddress”></div>

<h2>Send Payment</h2>
<input type=”text” id=”amount” placeholder=”Amount (USDC)” />
<button id=”sendPayment”>Send</button>

<script>
let provider, signer;
document.getElementById(‘connectWallet’).onclick = async () => {
if (window.ethereum) {
provider = new ethers.providers.Web3Provider(window.ethereum);
await provider.send(“eth_requestAccounts”, []);
signer = provider.getSigner();
const address = await signer.getAddress();
document.getElementById(‘walletAddress’).innerText = `Connected: ${address}`;
} else {
alert(“Install MetaMask!”);
}
};
</script>
</body>
</html>
“`

—

## πŸ› οΈ **Next Steps**
1. **Set up the repo**:
“`bash
mkdir FirstChainPay && cd FirstChainPay
git init
npx hardhat init # Choose “JavaScript project”
npm install @openzeppelin/contracts ethers
“`
2. **Deploy the contract**:
“`bash
npx hardhat run scripts/deploy.js –network mumbai
“`
3. **Start the frontend**:
“`bash
npx create-next-app frontend
cd frontend && npm install ethers wagmi @rainbow-me/rainbowkit
“`

—

## πŸ“Œ **Business Alignment**
– **FirstCloud.es** can use this as a **client demo** for blockchain consulting.
– Later, monetize via:
– Transaction fees (0.1% per cross-border payment)
– White-label solutions for enterprises

Let me know if you’d like to refine any component!

### 1. **Smart Contract (`PaymentGateway.sol`)**
```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

contract PaymentGateway {
    address public owner;
    mapping(address => uint256) public balances;

    constructor() {
        owner = msg.sender;
    }

    // Deposit ERC-20 tokens into the gateway
    function deposit(address token, uint256 amount) external {
        IERC20(token).transferFrom(msg.sender, address(this), amount);
        balances[msg.sender] += amount;
    }

    // Withdraw tokens (simplified; add security checks later)
    function withdraw(address token, uint256 amount) external {
        require(balances[msg.sender] >= amount, "Insufficient balance");
        IERC20(token).transfer(msg.sender, amount);
        balances[msg.sender] -= amount;
    }
}

Categories // Unix

Have hands-on experience on a broad range of real-world blockchain and fintech development patterns, including:

05.19.2025 by pablovillaronga //

blockchain technology explained feature
  • Smart contract development using Solidity (Ethereum) or Rust (Solana/Polkadot)
  • Blockchain integration with web or mobile apps (using Web3.js, Ethers.js, or libraries for Solana/Polygon/etc.)
  • Token creation (ERC-20, ERC-721, ERC-1155) and ICO/IDO structuring
  • Wallet integration (MetaMask, WalletConnect, Ledger)
  • Security considerations (smart contract vulnerabilities, audits, multi-sig wallets, KYC/AML implications)
  • Regulatory landscapes for blockchain fintech in regions like the EU, US, and Asia
  • DeFi protocols, DEX development, and NFT marketplaces
  • Payment gateways and custodial vs. non-custodial models

βœ… Project Proposal: FirstChainPay – A Blockchain-based Cross-Border Payment Gateway

πŸ” Concept:

Develop a decentralized payment gateway on Ethereum (or a low-fee chain like Polygon or Base) that allows users to:

  • Send and receive crypto payments across borders.
  • Automatically convert between tokens (e.g., USDC ↔ EURC ↔ MATIC).
  • Track transactions and generate invoices.
  • Integrate with existing e-commerce sites via a simple API or plugin.

🧱 Key Features

FeatureDescription
Smart ContractsWritten in Solidity to handle payment routing, conversion logic, and escrow.
Fiat-crypto bridge (mocked initially)Simulated KYC and fiat onboarding/offboarding flows (later link to services like Ramp or MoonPay).
DashboardAdmin and user-facing interfaces built with React + Tailwind (or Next.js) with wallet login (MetaMask, WalletConnect).
Multi-chain Support (future)Begin on one chain (Polygon or Ethereum testnet), later expand to Solana or Arbitrum.
Security ModuleInclude 2FA login for admin, multisig for contract upgrade/auths.
API/WebhooksAllow third-party e-commerce platforms to integrate it.
Invoicing SystemAuto-generate PDF invoices after payment, with blockchain TX hash.

BlockChain Definition:

The BLOCKCHAIN is a database technology that can maintain a growing list of data seemingly without limits that is decentralised and founded on the principle that it impossible to tamper with. The data records are combined in small blocks.  In order to add these blocks of data to the distributed ledger, which holds all the data and history of the blockchain, the data needs to be verified by atleast 51% of the computers that have access to the netwrok.

For data to be verified and added to the open ledger a method of cryptography is used. This means that a mathematical equation must be solved.  Simply put, once that mathematical equation is solved it will receive a stamp and a hash*. To solve the mathematical equation requires computing power. A verified trasnsaction can involve cryptocurrency, smart contracts, records or any type of information.

As mentioned above, this technology can be used to create cryptocurrencies. This technology allows peer to peer transactions without the need of a centralised authority such as a bank.  This will allow for transactions, nearly instantly to be achieved with no middle man that takes commission on the transaction.  To date there are already hundreds of cryptocurrencies running on this technology with Bitcoin being the most known and accepted.

πŸ› οΈ Tech Stack

  • Smart Contracts: Solidity + Hardhat/Foundry
  • Frontend: Next.js (React) + TailwindCSS
  • Blockchain: Polygon Mumbai testnet (then Polygon mainnet)
  • Web3: Ethers.js or Wagmi.sh + RainbowKit for wallet integration
  • Backend (optional): Node.js or Firebase Functions for metadata, user management, invoice generation
  • Storage: IPFS or Arweave (for optional metadata/files)
  • CI/CD & Hosting: Vercel or Netlify for the frontend, GitHub Actions for smart contract tests/deployments

πŸ§ͺ Phase 1 – MVP Timeline (8 Weeks)

WeekGoal
1Project repo setup, define scope, create GitHub project board
2Build & test basic ERC-20 payment smart contract
3Deploy to Polygon Mumbai, connect frontend with Ethers.js
4Add wallet login, build user dashboard UI
5Implement transaction history + mock invoice generation
6Add admin dashboard + basic API for payments
7Implement webhook to simulate e-commerce integration
8Final polish, test security (reentrancy, overflows), deploy to mainnet

πŸ’‘ Business Add-on (Optional)

You can build:

  • A course/blog/tutorial series under FirstCloud.es titled β€œBuilding Real-World Blockchain Fintech Products”.
  • A case study PDF downloadable by clients looking for blockchain services.
  • A demo site with fake USD/EUR tokens to simulate real-world testing for client demos.

Categories // Unix

In-Place Upgrade from Windows Server 2003 to Windows Server 2025 with Active Directory Schema Update

05.17.2025 by pablovillaronga //

With the release of Windows Server 2025, many organizations are looking to modernize their aging infrastructure. However, if you’re running a Domain Controller (DC) on Windows Server 2003, be aware that direct in-place upgrades to Windows Server 2025 are not supported.

This article outlines a multi-step upgrade path to bring your AD environment from Windows Server 2003 to Windows Server 2025, ensuring both functional continuity and schema compatibility.


🚨 Important Notes Before You Begin

  • No direct in-place upgrade from 2003 to 2025 is supported. You’ll need to upgrade through at least one intermediate OS, such as:
    • Windows Server 2003 β†’ 2008 R2 β†’ 2012 R2 β†’ 2019 β†’ 2025
  • This article focuses on schema updates and Domain Controller modernization.
  • In-place upgrades should only be done if absolutely necessary; Microsoft strongly recommends migrating to newer servers and promoting them instead.

🧰 Prerequisites

  • A complete system and Active Directory backup of the 2003 server.
  • Functional and healthy AD environment (test using dcdiag and netdiag).
  • The Windows Server 2003 DC is running SP2.
  • Upgrade media for intermediate versions (2008 R2, 2012 R2, 2019, 2025).
  • Sufficient hardware to meet modern OS requirements.
  • FSMO roles transferred, or a strategy to migrate them properly.

πŸ”„ Step-by-Step Upgrade Path

You must first upgrade the schema and then upgrade the DCs through intermediate versions.


🧱 Step 1: Upgrade Active Directory Schema for Windows Server 2008 R2

On your Windows Server 2003 Schema Master:

  1. Insert the Windows Server 2008 R2 DVD.
  2. Run: adprep32 /forestprep adprep32 /domainprep

adprep32 is used on 32-bit servers. If on 64-bit, use adprep.

  1. Wait for confirmation messages and ensure replication is complete.

πŸ’» Step 2: In-Place Upgrade to Windows Server 2008 R2

  1. Boot into Windows Server 2003.
  2. Run setup from Windows Server 2008 R2 DVD.
  3. Choose Upgrade option.
  4. Complete the upgrade wizard and allow the server to reboot.

Test domain functionality using:

dcdiag
repadmin /replsummary

πŸͺœ Repeat Upgrade Process

Repeat schema upgrades and OS upgrades through these steps:

πŸ‘‰ 2008 R2 to 2012 R2

  • Run adprep /forestprep and adprep /domainprep from 2012 R2 media.
  • Then do in-place upgrade to Windows Server 2012 R2.

πŸ‘‰ 2012 R2 to 2019

  • Again, run adprep /forestprep and adprep /domainprep from 2019 media.
  • Perform in-place upgrade to Windows Server 2019.

πŸ‘‰ 2019 to 2025

  • Run adprep /forestprep and adprep /domainprep from Windows Server 2025 media.
  • Finally, do in-place upgrade to Windows Server 2025.

πŸ” Schema Version Reference

Each schema update bumps the objectVersion:

Windows ServerSchema Version
200330
2008 R247
2012 R269
201687
201988
2025TBD (expected > 88)

Check schema version using:

reg query "HKLM\SYSTEM\CurrentControlSet\Services\NTDS\Parameters" /v "Schema Version"

Or:

ldifde -f export.txt -d "cn=schema,cn=configuration,dc=domain,dc=com" -l objectVersion

βœ… Post-Upgrade Validation

After reaching Windows Server 2025:

  1. Run dcdiag and repadmin /showrepl.
  2. Check DNS and SYSVOL replication.
  3. Confirm that Group Policies, login scripts, and replication function as expected.
  4. Optionally raise the domain and forest functional levels using Active Directory Domains and Trusts.

πŸ’‘ Migration Tip

Instead of in-place upgrades, a better long-term approach is:

  • Stand up a new Windows Server 2025 machine.
  • Promote it to a DC using dcpromo (or Server Manager).
  • Transfer FSMO roles.
  • Demote and decommission the old Windows Server 2003 DCs.

This method is cleaner, safer, and future-proof.


Conclusion

While it’s technically possible to upgrade from Windows Server 2003 to 2025 via in-place upgrades and schema updates, the process is multi-step and risky. Whenever feasible, build a modern AD environment on fresh hardware or VMs, then migrate.

If you’re looking for assistance in planning, executing, or automating Active Directory modernization, contact our team to get expert help tailored to your environment.


Would you like this article formatted for WordPress (with proper headings and shortcodes), a downloadable PDF version, or turned into a step-by-step video script?

Categories // Unix Tags // 2025, from Windows 2003, Upgrades, Windows

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